1. Field of the Invention
The present invention concerns a lock adapted to be accommodated within the thickness of an opening panel, to be actuated from either side of said opening panel by an operating member and/or a key, and to allow retraction of the latch bolt from the outside only by means of the key, this lock having two nuts rotatable about a common axis and attached to respective corresponding operating members.
The present invention is generally concerned with a lock, an espagnolette bolt lock or the like, of the aforementioned type, for doors, French windows or the like.
2. Description of the Prior Art
Many different locks of this type are known in themselves and are generally in the form of espagnolette bolt locks adapted to operate simultaneously a latch bolt, a lock bolt and at least one operating link.
In locks of this known type the mechanical members or the functions of the lock are controlled differently according to whether the user is on the inside or on the outside of the opening panel fitted with the lock. The objective is to lock the opening panel as soon as the user leaves the room to which it gives access. It is a question of making the lock inviolable by a third party on the outside of the opening panel who does not have the key. The opening panel can be unlocked only with the key. It is the latch bolt that locks the opening panel. Locks of this kind are usually fitted to apartment front doors.
One such lock is described in FR-A-2 657 385, for example. This lock includes a conventional nut attached to the inside operating member and which assures all the functions of a conventional espagnolette bolt lock. It also has a second nut attached to the exterior operating member which is adapted to engage with the square shaft operating the first nut through coupling means such that the nut attached to the outside operating member has a lost motion in one direction or the other before it is able to entrain the main nut. This lost motion prevents operation of the latch bolt by the outside operating member.
This lock requires the use of a support plate that has to be applied to the exterior face of the opening panel. Also, it is not reversible, i.e. when the lock is fitted to the opening panel it is not possible to choose, from the point of view of an observer regarding the lock accommodated within the thickness of the opening panel, whether the righthand side or the lefthand side should correspond to the exterior of the room to which the opening panel provides access.
Other locks of the aforementioned type known in themselves include two conventional nuts. These locks are thicker than conventional locks with the result that they cannot be accommodated in the slot usually made within the thickness of an opening panel. This makes it necessary either to increase the width of the slot, which weakens the opening panel, or to transfer to the exterior of the lock, for example inside cover plates, functions for which the mechanical parts cannot be housed within a standard size lock casing.
An aim of the present invention is to eliminate the drawbacks of the systems known in themselves and to propose a lock of the aforementioned type that is very easily and very simply reversible and which enables all of the mechanisms of a lock of this kind to be housed within a standard thickness casing.